Used printer cartridges of fax machines, copiers, inkjet printers, and laser printers are often remanufactured. The remanufacturing of printer cartridges may include cleaning, repairing damaged parts, replacing worn parts, and adding toner. The parts of printer cartridges typically include a toner hopper, a waste hopper, primary charge roller (PCR), a developer roller, and a drum.
Generally, printers embed toner on paper by relying on electrical charges occurring within the printer cartridges. The toner is typically stored in the toner hopper and carries a negative charge. The drum is typically given a charge by the PCR. The charge of the drum is typically more positive than the charge of the toner, and thus the drum is able to attract the toner. Once the drum is given a charge by the PCR and a print pattern is set, the drum gets coated with toner.
The toner may be carried to the drum by the developer roller (sometimes referred to as a “mag roller”), which may also preserve the uniform electrical charge of the toner. A doctor blade (sometimes referred to as a “doctor bar”) may be provided and positioned proximate to the developer roller with a predetermined distance. The doctor blade ensures that the right amount of toner sticks to the developer roller. If there is an excess amount of toner on the developer roller, the doctor blade scrapes off the excess amount. The developer roller then transfers the toner to the drum. The drum that is coated with toner then rolls over a sheet of paper, which is usually given a negative charge by the PCR. The charge of the paper is less negative than the charge of the toner, and thus the paper attracts the toner. The toner is embedded on the paper according to the print pattern.
The doctor blade and the developer roller are usually detached from printer cartridge during remanufacturing for cleaning. After cleaning, the doctor blade and the developer roller are reassembled together usually by hand and a screw driver. An assembler usually positions the doctor blade above the developer roller. The assembler would press on one side of the doctor blade then screw the same side of the doctor blade to the cartridge. The assembler would then execute the same steps on the remaining side.
The applicant has observed that this conventional method of assembly may not provide a uniform distance between the doctor blade and the developer roller from one side of the doctor blade to the other. As a result, the print quality may be affected, as the toner level on the developer roller is not effectively regulated by the doctor blade. One side of the roller may produce darker image than the other, or vice-versa. Methods and apparatus for effectively assembling the doctor blade proximate to the developer roller are desired and are addressed by the present invention.
Next, the toner hopper is typically refilled with toner during remanufacturing. Toner is typically introduced into the toner hopper either by drilling a hole, refilling the toner, then covering the hole, or by filling the toner hopper with toner through an existing toner hopper recess. Typically, these steps are executed by hand and a drill. At least one problem with the conventional technique is that the toner hopper is not secured throughout the process. The toner hopper may move during the drilling or the refilling steps, which may add to the time it takes to complete the refilling process. This additional time is undesirable in a high volume manufacturing environment. Moreover, the conventional technique may not produce uniform sized hopper holes for introducing the toner. Some hopper holes may be too small for refilling the toner, and some hopper holes may be too big to cover after refilling. Methods and apparatus for effectively refilling the cartridge with toner are desired and are addressed by the present invention.